Im going to be buying a set of 1 5/8 headmans and the matching y-pipe. I know the y-pipe collector is 2.5" pipe, should I get a 2.5" super turbo or go for the 3" hooker?

The car is a lg4 with 14x3 K&N and will soon have a holley intake and upgraded ignition.

 

cut off the 2.5 inch portion and weld up 3 inch to it and go 3 inch from there back.

 

Yes get the 3" Hooker you wont be disappointed.

 

on an LG4 I doubt you'll find an advantage with the 3". I wouldn't consider the size when making your decision... make it based on the other differences (price, sound, etc).

 

I agree. I have a 2.5" collector on my flowtechs and at first I though "oh great, this is not 3" but then I had to think that this motor will never really make enough power to need anything greater. When I step up to another motor down the road than a 3" collector is a must. Save yourself the time and money and use the set of headers that you have picked out. Install them and enjoy them.

 

I disagree. The stock 3 inch TPI exhaust is a proven 12 rwhp gain on an otherwise stock 305 tbi. 3 inch is critical when chooising an exhaust/y pipe.

 

I bet you would see the same 12hp with a 2.5 on a stock 305 TBI as well. Anything is btter than stock that is why you see such a large jump. Dyno the two, one with 2.5 and one with 3 and I bet you would see similar numbers.

 

Go with the 3" system!

 

Do what I did..

https://www.thirdgen.org/techbb2/sho...hreadid=209924